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   VI-MotionCueing &gt; <a href="motioncueing_vi-motioncueing_tuning.htm">VI-MotionCueing tuning in VI-DriveSim</a>&nbsp;&gt;</p>
      <h1 class="p_Heading1" style="page-break-after: avoid;"><span class="f_Heading1">Second Step: High pass cut-off frequency and input gains</span></h1>

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<p class="p_Normal">The second fundamental operation in the tuning procedure is to choose the high pass cut off frequencies and input gains, in order to be compliant with the platform limits and to give the driver a satisfactory perception of motion. For each DOF, it is necessary to perform an initial tuning in which the correct combination of cut-off filtering/input gain are chosen:</p>
<p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">High values cut-off frequencies allow high values of input gains hence high accelerations peaks are provided maintaining the platform within its working area;</span></p><p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">Low values cut-off frequencies allow a better match of the vehicle behavior, but necessarily require smaller gains to avoid to reach the position limits.</span></p><p class="p_Normal">&nbsp;</p>
<p class="p_Normal">In the figures below a comparison between two different combinations of high pass cut-off frequency and gain are shown for the longitudinal dynamic. The two behaviors are obtained with the only difference of the high pass cut-off frequency and the longitudinal input gain: one is obtained with a high pass cut off freq of 1.5 Hz and 4 as gain and the other one with 2.5 Hz and 7 as gain. The position of the platform is very similar but the acceleration peak is almost 35 % bigger and narrower in the one with the higher values. The same approach should be used for the other DOFs, excluding the pitch and roll, due to the importance of the low frequency component for both. A very small value of cut-off freq is chosen and the gain is adjusted according to driver’s comments.</p>
<p class="p_Normal">&nbsp;</p>
<div class="p_Normal" style="text-align: center;"><div style="margin:0px auto 0px auto;width:788px"><img alt="&nbsp;Comparison of perceived longitudinal accelerations for two different combinations of high pass cut-off freqs and gains." title="&nbsp;Comparison of perceived longitudinal accelerations for two different combinations of high pass cut-off freqs and gains." width="788" height="478" style="width:788px;height:478px;border:none" src="mtncng_image13.png"/><p style="text-align:center"><span class="f_ImageCaption"><br/>
Comparison of perceived longitudinal accelerations for two different combinations of high pass cut-off freqs and gains.</span></p></div></div>
<p class="p_Normal">&nbsp;</p>
<p class="p_Normal">&nbsp;</p>
<p class="p_Normal">&nbsp;</p>
<div class="p_Normal" style="text-align: center;"><div style="margin:0px auto 0px auto;width:788px"><img alt="&nbsp;Comparison of longitudinal positions for two different combinations of high pass cut-off freqs and gains." title="&nbsp;Comparison of longitudinal positions for two different combinations of high pass cut-off freqs and gains." width="788" height="449" style="width:788px;height:449px;border:none" src="mtncng_image14.png"/><p style="text-align:center"><span class="f_ImageCaption"><br/>
Comparison of longitudinal positions for two different combinations of high pass cut-off freqs and gains.</span></p></div></div>
<p class="p_Normal">&nbsp;</p>

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